Project description:The fate of the carbon stocked in permafrost soils following global warming and permafrost thaw is of major concern in view of the potential for increased CH4 and CO2 emissions from these soils. Complex carbon compound degradation and greenhouse gas emissions are due to soil microbial communities, but their composition and functional potential in permafrost soils are largely unknown. Here, a 2 m deep permafrost and its overlying active layer soil were subjected to metagenome sequencing, quantitative PCR, and microarray analyses. The active layer soil and 2 m permafrost soil microbial community structures were very similar, with Actinobacteria being the dominant phylum. The two soils also possessed a highly similar spectrum of functional genes, especially when compared to other already published metagenomes. Key genes related to methane generation, methane oxidation and organic matter degradation were highly diverse for both soils in the metagenomic libraries and some (e.g. pmoA) showed relatively high abundance in qPCR assays. Genes related to nitrogen fixation and ammonia oxidation, which could have important roles following climatic change in these nitrogen-limited environments, showed low diversity but high abundance. The 2 m permafrost soil showed lower abundance and diversity for all the assessed genes and taxa. Experimental biases were also evaluated and showed that the whole community genome amplification technique used caused large representational biases in the metagenomic libraries. This study described for the first time the detailed functional potential of permafrost-affected soils and detected several genes and microorganisms that could have crucial importance following permafrost thaw.
Project description:The fate of the carbon stocked in permafrost soils following global warming and permafrost thaw is of major concern in view of the potential for increased CH4 and CO2 emissions from these soils. Complex carbon compound degradation and greenhouse gas emissions are due to soil microbial communities, but their composition and functional potential in permafrost soils are largely unknown. Here, a 2 m deep permafrost and its overlying active layer soil were subjected to metagenome sequencing, quantitative PCR, and microarray analyses. The active layer soil and 2 m permafrost soil microbial community structures were very similar, with Actinobacteria being the dominant phylum. The two soils also possessed a highly similar spectrum of functional genes, especially when compared to other already published metagenomes. Key genes related to methane generation, methane oxidation and organic matter degradation were highly diverse for both soils in the metagenomic libraries and some (e.g. pmoA) showed relatively high abundance in qPCR assays. Genes related to nitrogen fixation and ammonia oxidation, which could have important roles following climatic change in these nitrogen-limited environments, showed low diversity but high abundance. The 2 m permafrost soil showed lower abundance and diversity for all the assessed genes and taxa. Experimental biases were also evaluated and showed that the whole community genome amplification technique used caused large representational biases in the metagenomic libraries. This study described for the first time the detailed functional potential of permafrost-affected soils and detected several genes and microorganisms that could have crucial importance following permafrost thaw. A 2m deep permafrost sample and it overlying active layer were sampled and their metagenome analysed. For microarray analyses, 8 other soil samples from the same region were used for comparison purposes.
Project description:Nitrate-reducing iron(II)-oxidizing bacteria are widespread in the environment contribute to nitrate removal and influence the fate of the greenhouse gases nitrous oxide and carbon dioxide. The autotrophic growth of nitrate-reducing iron(II)-oxidizing bacteria is rarely investigated and poorly understood. The most prominent model system for this type of studies is enrichment culture KS, which originates from a freshwater sediment in Bremen, Germany. To gain insights in the metabolism of nitrate reduction coupled to iron(II) oxidation under in the absence of organic carbon and oxygen limited conditions, we performed metagenomic, metatranscriptomic and metaproteomic analyses of culture KS. Raw sequencing data of 16S rRNA amplicon sequencing, shotgun metagenomics (short reads: Illumina; long reads: Oxford Nanopore Technologies), metagenome assembly, raw sequencing data of shotgun metatranscriptomes (2 conditions, triplicates) can be found at SRA in https://www.ncbi.nlm.nih.gov/bioproject/PRJNA682552. This dataset contains proteomics data for 2 conditions (heterotrophic and autotrophic growth conditions) in triplicates.
Project description:Nitrate-reducing iron(II)-oxidizing (NDFO) bacteria are widespread in the environment contribute to nitrate removal and influence the fate of the greenhouse gases nitrous oxide and carbon dioxide. The autotrophic growth of nitrate-reducing iron(II)-oxidizing bacteria is rarely investigated and poorly understood. The most prominent model system for this type of studies is enrichment culture KS, which originates from a freshwater sediment in Bremen, Germany. A second NDFO culture, culture BP, was obtained with a sample taken in 2015 at the same pond and cultured in a similar way. To gain insights in the metabolism of nitrate reduction coupled to iron(II) oxidation under in the absence of organic carbon and oxygen limited conditions, we performed metagenomic, metatranscriptomic and metaproteomic analyses of culture BP. Raw sequencing data of 16S rRNA amplicon sequencing (V4 region with Illumina and near full-length with PacBio), shotgun metagenomics, metagenome assembly, raw sequencing data of shotgun metatranscriptomes (2 conditions, triplicates) can be found at SRA in https://www.ncbi.nlm.nih.gov/bioproject/PRJNA693457. This dataset contains proteomics data for 2 conditions in triplicates. Samples R23, R24, and R25 are grown in autotrophic conditions, samples R26, R27, and R28 in heterotrophic conditions.
Project description:During the COVID-19 pandemic, facemasks have played a pivotal role in preventing person-person droplet transmission of viral particles. However, prolonged facemask wearing causes skin irritations colloquially referred to as ‘maskne’ (mask + acne), which manifests as acne and contact dermatitis and is mostly caused by pathogenic skin microbes. Previous studies revealed that the putative causal microbes were anaerobic bacteria, but the pathogenesis of facemask-associated skin conditions remains poorly defined. We therefore characterized the role of the facemask-associated skin microbiota in the development of maskne using culture-dependent and -independent methodologies. Metagenomic analysis revealed that the majority of the facemask microbiota were anaerobic bacteria that originated from the skin rather than saliva. Previous work demonstrated direct interaction between pathogenic bacteria and antagonistic strains in the microbiome. We expanded this analysis to include indirect interaction between pathogenic bacteria and other indigenous bacteria classified as either ‘pathogen helper (PH)’ or ‘pathogen inhibitor (PIn)’ strains. In vitro screening of bacteria isolated from facemasks identified both strains that antagonized and promoted pathogen growth. These data were validated using a mouse skin infection model, where we observed attenuation of symptoms following pathogen infection. Moreover, the inhibitor of pathogen helper (IPH) strain, which did not directly attenuate pathogen growth in vitro and in vivo, functioned to suppress symptom development and pathogen growth indirectly through PH inhibitory antibacterial products such as phenyl lactic acid. Taken together, our study defines a mechanism by which indirect microbiota interactions under facemasks control symptoms of maskne by suppressing a skin pathogen for the first time.